In a beaker 26 g of hexamine is dissolved in 60 mL of very hot water and cooled down to 0°C, the beaker is then immersed in an ice bath. An addition of 79 g of 60% cold nitric acid is started with stirring while the temperature is maintained below 10°C. After the addition is complete the solution is stirred for additional 5 minutes, the mixture is filtered, washed with 200 mL of ethanol and dried in a desiccator. The pure HDN is hygroscopic so it may be stored with and drying agent pad.
Dissolving the hexamine in the water
The beaker immersed in an ice bath and an addition funnel set up
The cold mixture
The dry product